Applying variable Cp

I am solving one problem involving conjugate heat transfer using FLUENT. For the given problem Cp varies with temperature, with a sudden jump in Cp value at one particular temp. Can any one tell me how can we model this in FLUENT. I don't think this can be done by doing curve fitting since there is a huge jump in Cp value at one particular temp.

We modeled heat transfer of supercritical fluid with large sharp in cp, in which Cp is treated as three curve with temperatue which approaches the real values. So if the temperature is separated appropriately, Cp can be treated as the function of temperature well.